Journal of Ophthalmic and Vision Research
Volume:9 Issue: 2, Apr-Jun 2014

To compare choroidal thickness (CT) between individuals with and without glaucomatous damage and to explore the association of peripapillary and submacular CT with glaucoma severity using spectral domain optical coherence tomography (SD-OCT). Ninety-one eyes of 20 normal subjects and 43 glaucoma patients from the UCLA SD-OCT Imaging Study were enrolled. Imaging was performed using Cirrus HD-OCT. Choroidal thickness was measured at four predetermined points in the macular and peripapillary regions, and compared between glaucoma and control groups before and after adjusting for potential confounding variables. The average (± standard deviation) mean deviation (MD) on visual fields was -0.3 (±2.0) dB in controls and -3.5 (±3.5) dB in glaucoma patients. Age, axial length and their interaction were the most significant factors affecting CT on multivariate analysis. Adjusted average CT (corrected for age, axial length, their interaction, genderand lens status) however, was not different between glaucoma patients and the control group (P=0.083) except in the temporal parafoveal region (P=0.037); nor was choroidal thickness related to glaucoma severity (r=-0.187, P=0.176 for correlation with MD, r=-0.151, P=0.275 for correlation with average nerve fiber layer thickness). Choroidal thickness of the macular and peripapillary regions is not decreased in glaucoma. Anatomical measurements with SD-OCT do not support the possible influence of the choroid on the pathophysiology of glaucoma.

To evaluate the short-term effects of a single subconjunctival injection of triamcinolone acetonide as an adjunct to subconjunctival bevacizumab for prevention of corneal neovascularization in rats. Chemical cauterization was performed in the central cornea of the right eye in 48 male Sprague-Dawley rats (4 eyes were excluded due to perforation and/or infection). Immediately after the injury, the rats were randomly assigned to four treatment groups: controls (n = 10), received subconjunctival injection of 0.02 mL balanced salt solution; group 1 (n = 12), received 0.02 mL bevacizumab (25 mg/mL); group 2 (n = 11), were treated with 0.02 mL triamcinolone acetonide (40 mg/mL); and group 3 (n = 11), received both bevacizumab and triamcinolone acetonide. On days 7 and 14 after cauterization, digital photographs of the corneas were taken and the area of neovascularization was calculated and compared among the study groups. The area of corneal neovascularization in all three treatment groups was less than the controls (P < 0.05 for all comparisons). On day 7, the corneal avascular area was largest in group 3 (63 %). On day 14, the area of corneal neovascularization in groups 2 and 3 was smaller than that in group 1 (P = 0.031 and 0.011, respectively), but the difference between groups 2 and 3 was not statistically significant (P = 0.552). Microscopic evaluation of the cornea was compatible with gross findings; inflammation and the number of new vessels was the least in group 3. Triamcinolone acetonide was more effective than bevacizumab in inhibiting corneal neovascularization. Its adjunctive administration to bevacizumab resulted in even better prevention of corneal neovascularization. However, the produced combined effect was less than the sum of their separate effects and did not match additive or synergistic interactions.

To investigate the reliability of partial coherence laser interferometry for optical biometry in highly myopic eyes. Axial length measurements by the IOLMaster (Carl Zeiss Meditec, Germany) with signal-to-noise ratio (SNR) equal or more than 2 were performed in 52 consecutive myopic subjects with axial length equal or more than 26.5 mm and 45 emmetropic patients before cataract surgery. Axial length measurements and SNR were analyzed and compared among the two study groups. Axial length measurements were feasible in 46 of 52 (88.5%) highly myopic eyes and in 41 of 45 (91.1%) eyes with normal axial length. To achieve two reliable axial length values with SNR equal or more than 2, a mean number of 2.06±0.25 measurements was necessary in myopic eyes and 2.10±0.37 in emmetropic counterparts. Mean SNR after two measurements was 4.98±2.44 in myopic eyes versus 5.56±2.32 in control eyes. Even though successful measurement was independent of preoperative visual acuity, patients with visual acuity better than 20/63 showed significantly higher SNR values. Partial coherence laser interferometry shows satisfying feasibility and good signal quality for axial length determination in highly myopic eyes with stable retinal condition and clear media.

To assess the visual and refractive outcomes of flexible toric iris claw phakic intraocular lens implantation for correction of moderate to high myopia with astigmatism. In this non-randomized prospective study, 31 eyes of 18 patients including 8 male and 10 female subjects with mean age of 27.62±5.53 (range 19 to 38) years with moderate to high myopia and astigmatism underwent toric Artiflex (Ophtec BV, Groningen, Netherlands) phakic intraocular lens (PIOL) implantation. Uncorrected distance visual acuity (UDVA) and corrected distance visual acuity (CDVA) were measured in logarithm of minimum angle of resolution (logMAR) notations. Manifest refraction, safety, efficacy, predictability and complications were measured 6 months after surgery. Pre-operatively, mean spherical equivalent (SE) refractive error was -9.68±1.92 (range -14.00 to -6.00) diopter (D) and mean cylinder was -2.79±1.06 (range -4.75 to -1.00) D. After a minimum of 6 months, mean SE was -0.38±0.27 (range -0.87 to 0.00) D and mean cylinder was -0.66±0.43 (range -1.50 to 0.00) D. SE was within 0.50 D of emmetropia in 63.8% and within 1.0 D of target refraction in 100% of eyes. UDVA was equal or better than 20/20 in 45.1% of eyes while CDVA was equal or better than 20/20 in 67.7%; 83.8% of eyes gained 1 or more Snellen lines of CDVA after surgery. No serious complications occurred in this series of cases. Implantation of the toric Artiflex PIOL is a safe and effective procedure for correction of moderate to high myopia with astigmatism.

To determine the frequency of complement factor H (Y402H) and age related macular degeneration susceptibility gene 2 (A69S) single nucleotide polymorphisms in patients with age-related macular degeneration (AMD) and in matched non-AMD controls in an Iranian population. Seventy patients with AMD and 86 age- and sex-matched controls were recruited and examined. Peripheral blood sample was obtained from all subjects for DNA extraction and direct sequencing of Y402H and A69S genes. Odds ratios (ORs) with 95% confidence intervals (CIs) for the association of Y402H and A69S polymorphisms with AMD were determined. The frequencies of both homozygous and heterozygous genotypes were significantly higher in cases than controls for both Y402H and A69S polymorphisms. In comparison to the wild genotypes, OR for AMD associated with Y402H and A69S polymorphisms were 1.9 (95% CI, 1.1-3.2) and 2.2 (95% CI, 1.6-3.1), respectively. Joint risk analysis considering both genes revealed a higher risk of AMD when polymorphisms were present for both genes. Y402H and A69S polymorphisms were strongly associated with AMD in this Iranian population.

To discuss the clinical characteristics, treatment and outcomes of germline and non-germline retinoblastoma tumors. A retrospective study was performed on retinoblastoma cases from 1979 to 2007. General characteristics of the patients, treatment modalities, histopathological findings and survival were compared in germline versus non-germline cases. We analyzed 557 cases of retinoblastoma with mean age of 32.2±22.0 months including 177 and 380 patients with germline and non-germline tumors, respectively. Germline cases were significantly different from non-germline counterparts in terms of mean age (24.7±17.7 vs 35.7±23.0 months), symptoms (leukocoria in 49.4% vs 62.9%), and outcomes (death in 40.1% vs 13.9%), respectively (P<0.001). In the germline group 66.5% and in non-germline group over 97% of patients had stage Va or higher (ICRB D-E disease). Disease-free survival was 48.6% for germlines cases versus 80.9% for nongermline patients (with mean follow up of 61.9 months, P<0.001). Histopathologically, more invasions to intraocular and extraocular tissues were seen with non-germline tumors of (66% vs 39.8%). Mortality rates in germline cases and non-germline were 40.1% and 13.9%, respectively (P<0.001). Despite higher tumor staging in nongermline cases at the time of diagnosis and therefore more aggressive behavior of the tumor, germline cases had a higher rate of mortality during the follow up period.

To evaluate electroretinogram (ERG) changes in the contralateral normal appearing eye of patients with unilateral acute necrotizing herpetic retinitis (NHR). This interventional case series includes subjects with acute unilateral NHR. All patients were treated with intravenous followed by oral acyclovir and systemic steroids. Main outcome measures were changes in a- and b-wave amplitudes of scotopic and photopic full-field ERG in the sound eye, 1 and 3 months after therapy as compared to baseline. Twenty normal subjects served as controls. Forty eyes of 20 patients including 12 male and 8 female subjects with mean age of 44.1±11.5 (range 22 to 66) years were studied. Twenty unaffected eyes were the subject of the current study. The retina in all of these eyes remained intact during the course of the study. In the sound eyes, mean b-wave amplitude of the maximal combined response ERG before initiation of treatment was 229.5±38.8 microvolts which increased to 356.1±34.0 (P<0.001) and 365.8±32.7 (P<0.001) microvolts 1 and 3 months after treatment, respectively. Corresponding figures for b-wave amplitudes of the cone response ERG were 24.9±6.0, 47.0±12.9 (P<0.001) and 52.8±12.7 (P<0.001) microvolts, respectively. Visual acuity of all sound eyes remained unchanged throughout the study. Despite normal retinal appearance and intact visual acuity in the sound eyes of patients with NHR, electrophysiological changes were observed. Prompt diagnosis and management of NHR and continuation of medication for 3 months may reverse subclinical ERG changes and reduce the risk of progression to overt clinical disease.

To investigate the retinal biocompatibility of Brilliant Blue G with deuterated water (BBG-D2O) as a vital dye for chromovitrectomy. In this animal study, 0.05 mL of 0.25 g/L Brilliant Blue G (BBG) associated with 0.13 mL/mL of deuterium oxide (D2O) was injected intravitreally in the right eye and the same amount of balanced salt solution (BSS) was injected similarly in the left eye of rabbits. Clinical examination and histology with light microscopy were performed after seven days. Retinal cell layers were evaluated for morphologic alterations. Electroretinographic (ERG) changes were also assessed at baseline and 7 days after the injections. A total of 6 rabbits were included in the study. The gross histopathologic appearance of the retina, choroid, sclera and optic nerve was within normal limits without any sign of severe retinal necrosis or cystic degeneration. Light microscopy showed that BBG-D2O caused no substantial alterations in retinal layers as compared to control eyes. The injection of BBG-D2O did not induce considerable functional ERG alterations. Intravitreal injection of BBG-D2O 0.25 g/L seems to induce no retinal toxicity as documented by lack of functional and histological changes.

To report the clinical features, and anatomic and visual outcomes of pediatric retinal detachment (RD) surgery at a tertiary referral center in Southern Iran. In this retrospective, non-comparative, interventional case series, we reviewed the records of 77 patients less than 18 years of age who had undergone primary RD surgery at Khalili Hospital, Shiraz, Iran from 2005 to 2010. All patients had follow-up duration more than 12 months. Seventy-seven eyes of 77 patients with mean age of 12.5±5 (range, 2-18) years including 56 (73%) male subjects were included. The most common etiologies of RD included trauma (90%) and myopia (6%). Different types of breaks and proliferative viteroretinopathy were present in 75% and 13% of eyes, respectively. The most common primary surgery was deep viterectomy (78%) followed by scleral buckling (19.5%). Single-operation reattachment was accomplished in 55% of cases. At final follow up, functional visual loss [best corrected visual acuity (BCVA) <5/200] occurred in 66.7%, while the rate of anatomical success was 62.3%. Significant predictors of better final BCVA were higher initial BCVA (P=0.015), absence of relative afferent pupillary defect (P=0.002), less extensive RD (P=0.031), and primary RD surgery (P=0.056). Anatomical success was associated with a lower number of procedures (P<0.001) and marginally with phakic lens status (P=0.079). Trauma was the most prevalent predisposing factor for pediatric RD in our study. The high rates of functional visual loss and low anatomical success may be due to a large proportion of trauma and the complex nature of RD.

To report micro- and ultrastructural features of internal limiting membranes (ILMs) in various maculopathies and to evaluate the effects of indocyanine green (ICG) and triamcinolone acetonide (TA) on epiretinal proliferations associated with ILM and on retinal cleavage plane. ILMs from various maculopathies were evaluated regarding presence or absence of membrane-associated cells, type of cells and ILM thickness based on routine histopathology, immunohistochemistry and transmission electron microscopy (TEM). Thirty ILM specimens were enrolled; 25 of which were evaluated by histopathology and immunohistochemistry and 5 by TEM. ICG only had been used in 17 specimens, TA in 4, and both agents in one specimen. The majority of specimens were immunoreactive for glial fibrillary acidic protein and neuron specific enolase. No significant difference in specimen cellularity and alteration of cleavage plane was noted between ICG-stained and non-ICG-stained ILMs or between TA-assisted and non-TAassisted ones. Excluding central retinal vein occlusion (CRVO) cases, acellularity was not observed in any of ILMs from diabetic macular edema (DME), cystoid macular edema (CME), and traumatic macular hole (TMH) eyes. TEM disclosed ILM thickening and cellularity in DME as compared to CRVO. Acellular membranes from CRVO maculopathy may be a sequel of acute retinal ischemia. Thickened diabetic ILMs with high cellularity may be related to chronic activation of Muller cells. No obvious influence of ICG or TA on epiretinal cellularity was detected and the dyes seem to have no significant effect on cleavage plane.

To determine general awareness and knowledge about cataracts, glaucoma and diabetic retinopathy (DR), as common avoidable causes of blindness in an Iranian population. This cross-sectional population-based survey was performed on residents over 45 years of age in Tehran. The sampling frame was the list of all landline phone numbers registered by the Telecommunications Center of Iran, through which systematic random sampling was performed. Data was collected by phone-call interviews and completing a semi-structured questionnaire. Awareness was defined as whether the respondent had ever heard of the disease. Knowledge was assessed by realizing different aspects of each disease. Of a total of 1,084 eligible people including 574 (52.9%) women and 510 (47.1%) men were included and 957 subjects (response rate, 88.3%) completed the interview. Awareness regarding glaucoma, cataract and DR was 46.6% (95% confidence interval [CI]:43.4 -49.8%), 82.9% (95% CI: 80.5 -85.3%) and 86.2% (95% CI: 84-88.4%). In addition, 19.2% (95% CI: 16.7 -21.7%), 57.3% (95% CI: 54.2-60.4%) and 72% (95% CI: 69.2 -74.8%) of respondents could give at least a basic definition of the mentioned diseases, respectively. Only 22.6% (95% CI: 20-25.2%) and 41.6% (95% CI: 38.5-44.7%) realized glaucoma and DR as a treatable condition; in contrast, 77.2% (95% CI: 74.5-79.9%) categorized cataract as treatable. Only 19% and 7.1% knew that DR and glaucoma may commence without any apparent symptoms. Compared with cataract and DR, most participants had limited information about glaucoma. In addition, few of the respondents were familiar with the initial symptoms of DR and glaucoma.

To determine the prevalence of refractive errors among high school students. In a cross-sectional study, we applied stratified cluster sampling on high school students of Aligoudarz, Western Iran. Examinations included visual acuity, non-cycloplegic refraction by autorefraction and fine tuning with retinoscopy. Myopia and hyperopia were defined as spherical equivalent of -0.5/+0.5 diopter (D) or worse, respectively; astigmatism was defined as cylindrical error >0.5 D and anisometropia as an interocular difference in spherical equivalent exceeding 1 D. Of 451 selected students, 438 participated in the study (response rate, 97.0%). Data from 434 subjects with mean age of 16±1.3 (range, 14 to 21) years including 212 (48.8%) male subjects was analyzed. The prevalence of myopia, hyperopia and astigmatism was 29.3% [95% confidence interval (CI), 25-33.6%], 21.7% (95% CI, 17.8-25.5%), and 20.7% (95% CI, 16.9-24.6%), respectively. The prevalence of myopia increased significantly with age [odds ratio (OR)=1.30, P=0.003] and was higher among boys (OR=3.10, P<0.001). The prevalence of hyperopia was significantly higher in girls (OR=0.49, P=0.003). The prevalence of astigmatism was 25.9% in boys and 15.8% in girls (OR=2.13, P=0.002). The overall prevalence of high myopia and high hyperopia were 0.5% and 1.2%, respectively. The prevalence of with-the-rule, against-the-rule, and oblique astigmatism was 14.5%, 4.8% and 1.4%, respectively. Overall, 4.6% (95% CI, 2.6-6.6%) of subjects were anisometropic. More than half of high school students in Aligoudarz had at least one type of refractive error. Compared to similar studies, the prevalence of refractive errors was high in this age group.

Keratoconjunctivitis sicca, or dry eye, is a common ocular disease prompting millions of individuals to seek ophthalmological care. Regardless of the underlying etiology, dry eye has been shown to be associated with abnormalities in the pre-corneal tear film and subsequent inflammatory changes in the entire ocular surface including the adnexa, conjunctiva and cornea. Since the recognition of the role of inflammation in dry eye, a number of novel treatments have been investigated designed to inhibit various inflammatory pathways. Current medications that are used, including cyclosporine A, corticosteroids, tacrolimus, tetracycline derivatives and autologous serum, have been effective for management of dry eye and lead to measurable clinical improvement.

Adequate visualization and identification of the posterior hyaloid, epiretinal membranes and the internal limiting membrane are of paramount importance in modern vitreoretinal surgery. “Chromovitrectomy” is a term used for describing the vital dyes use in order to stain these transparent tissues and facilitate their manipulation during vitreous surgery. This article reviews the indications, applications and characteristics of vital dyes in vitreoretinal surgery. Various dyes are currently being used in routine clinical procedures, however the ideal staining agent has not yet been found. Any dye which is injected intravitreally has the potential to become toxic. Triamcinolone acetonide is used to highlight the vitreous and is particularly beneficial in determining the attachment of the posterior hyaloid to the underlying retina. Trypan blue stains epiretinal membranes and facilitates their complete removal. Both indocyanine green and brilliant blue G stain the internal limiting membrane properly, however concerns over indocyanine green toxicity have made surgeons switch to brillliant blue G as a safer alternative.

Intraocular pressure (IOP) is the only treatable risk factor for glaucoma. Yet, current glaucoma management usually relies on single IOP measurements during clinic hours despite the fact that IOP is a dynamic parameter with individual rhythms. Single IOP measurements underpin all major clinical guidelines on treatment of glaucoma. Other potentially informative parameters, such as IOP fluctuations and peak IOP, have been neglected, and effects of IOP-lowering interventions on such measures are largely unknown. The search for continuous 24-hour IOP monitoring started over 50 years ago, but only recent technological advances have provided clinician-researchers with devices for continuous IOP monitoring. Herein, we discuss innovative approaches with permanent and temporary devices for 24-hour IOP monitoring, such as a contact lens sensor. Despite being in their infancy, these devices may soon enable clinicians to use 24-hour IOP data to improve glaucoma management and reduce the glaucoma-related burden of disease.

To report corneal findings in a familial case of the crystalline subtype of pre-Descemetic corneal dystrophy. Case Report: A 19-year-old girl and her 44-year-old mother were found to have asymptomatic, bilateral, punctiform and multi-colored crystalline opacities across the whole posterior layer of the corneas. Endothelial specular microscopy revealed the presence of white round flecks located at different levels anterior to the endothelium. No systemic abnormalities or medications could be related to account for these findings. To the best of our knowledge, this is the third familial report of this rare corneal disorder. Differential diagnosis may include Schnyder corneal dystrophy, cystinosis, Bietti´s dystrophy and monoclonal gammopathy.

To report a patient with a single cotton wool spot (CWS) following head trauma. Case Report: A 37-year-old male electrician presented with painless paracentral blurred vision in his left eye of one month duration together with three transient episodes of obscuration of vision in the same eye lasting for 10 minutes. He reported blunt head trauma due to a fall 40 days before referral. Fundus examination at presentation was normal but after 4 months, revealed the appearance of a white spot along the superotemporal arcade in the absence of other fundus lesions. A comprehensive systemic workup was performed revealing no specific findings. Ophthalmoscopic examination after 6 weeks disclosed resolution of the CWS with no intervention. The patient’s complaint of paracentral visual field defect improved and subsequent optical coherence tomography showed retinal thinning in that area. Herein, we report a patient with a single CWS near the optic disc four months after head trauma along with normal systemic and paraclinical evaluations. Head trauma may thus be considered as a cause of CWS.

Removal of particulate materials from the retinal surface is somewhat difficult during small gauge vitrectomy. Simple injection of balanced salt solution into the vitreous cavity in a controlled manner using a connector tubing between the syringe and needle can produce enough turbulence to float the deposited material and remove it.